Caking of the conveyor belt occurs nonuniformly over the width of the belt and the length of the belt. The caking adheres nonuniformly firmly to the belt; it is also nonuniform in terms of its layer thickness.
So called end strippers are strippers which are fitted at the belt discharge point, directly under the discharge parabel, at the drive roller; they remove the caking on the conveyor belt more or less intensively. Transversely acting strippers at the discharge point are frequent.
Such transversely acting strippers, known in practice, may be subdivided into those which effect more intensive cleaning and those which effect less intensive cleaning. The so-called slat stripper has primarily become widespread nowadays as a transversely acting stripper. However, this stripper only satisfies the object set to a certain extent. It comprises a steel housing or an axle equipped over its length with a number of flat slats or modules. These are spring-mounted and thus bring about a different contact pressure, but this is uniform only over the respective track width.
The contact pressure of the conveyor belt against the drive drum is very high, caused by the high tractive force of the drum, as a result of which relatively low elevations or depressions in the belt only ever allow the slats to act at the highest point of the unevenness. If an encrustation on the belt cannot be detached by the slats, or if the belt has not been repaired, by means of applied patches, in such a way that the belt surface is completely even, in the surrounding area the adhering soiling on the belt is not stripped off. If, in addition, the belt is further damaged by depressions (grooves or detached, upper belt-ply cover sheets), then the soiling remains adhering there as well.
The same is to be feared when the drive drum has worn nonuniformly and, as a result, the belt surface in the region of the strippers is not even. In order to permit the conveyor belt to move to the left and right, the drive drums are often crowned, that is to say their diameter decreases from the center toward the ends, which means that the drive drum is highest at the center. In the case of such crowned drums, cleaning using standard transversely acting strippers cannot be achieved at all.